package net.aooms.core.util;
/*

 * Password Hashing With PBKDF2 (http://crackstation.net/hashing-security.htm).

 * Copyright (c) 2013, Taylor Hornby

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *

 * 1. Redistributions of source code must retain the above copyright notice,

 * this list of conditions and the following disclaimer.

 *

 * 2. Redistributions in binary form must reproduce the above copyright notice,

 * this list of conditions and the following disclaimer in the documentation

 * and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE

 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

 * POSSIBILITY OF SUCH DAMAGE.

 */

import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import java.math.BigInteger;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.InvalidKeySpecException;

/*

 * PBKDF2 salted password hashing.

 * Author: havoc AT defuse.ca

 * www: http://crackstation.net/hashing-security.htm

 */

public class PasswordUtils

{

    public static final String PBKDF2_ALGORITHM = "PBKDF2WithHmacSHA1";

    // 盐值
    private static final String SALT = "1s;'a;123`-123,c.efjwuwidncmsoo123.da~!@#$%HNM.?;''{00djlsdlkkdkdk";

    // The following constants may be changed without breaking existing hashes.

    public static final int SALT_BYTE_SIZE = 24;

    public static final int HASH_BYTE_SIZE = 24;

    public static final int PBKDF2_ITERATIONS = 220480; // 1024

    public static final int ITERATION_INDEX = 0;

    public static final int SALT_INDEX = 1;

    public static final int PBKDF2_INDEX = 2;

    //原密码加上盐值
    private static String convertPassword(String password) {
        return (password + "::" + SALT);
    }

    /**
     * Returns a salted PBKDF2 hash of the password.
     *
     * @param password the password to hash
     * @return a salted PBKDF2 hash of the password
     */
    public static String createHash(String password) {
        try {
            return createHash(convertPassword(password).toCharArray());
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * Returns a salted PBKDF2 hash of the password.
     *
     * @param password the password to hash
     * @return a salted PBKDF2 hash of the password
     */

    private static String createHash(char[] password)
            throws NoSuchAlgorithmException, InvalidKeySpecException {

        // Generate a random salt

        SecureRandom random = new SecureRandom();

        byte[] salt = new byte[SALT_BYTE_SIZE];

        random.nextBytes(salt);

        // Hash the password

        byte[] hash = pbkdf2(password, salt, PBKDF2_ITERATIONS, HASH_BYTE_SIZE);

        // format iterations:salt:hash

        return PBKDF2_ITERATIONS + ":" + toHex(salt) + ":" + toHex(hash);

    }

    /**
     * Validates a password using a hash.
     *
     * @param password    the password to check
     * @param correctHash the hash of the valid password
     * @return true if the password is correct, false if not
     */

    public static boolean validatePassword(String password, String correctHash) {
        try {
            return validatePassword(convertPassword(password).toCharArray(), correctHash);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return false;
    }

    /**
     * Validates a password using a hash.
     *
     * @param password    the password to check
     * @param correctHash the hash of the valid password
     * @return true if the password is correct, false if not
     */

    private static boolean validatePassword(char[] password, String correctHash)

            throws NoSuchAlgorithmException, InvalidKeySpecException

    {

        // Decode the hash into its parameters

        String[] params = correctHash.split(":");

        int iterations = Integer.parseInt(params[ITERATION_INDEX]);

        byte[] salt = fromHex(params[SALT_INDEX]);

        byte[] hash = fromHex(params[PBKDF2_INDEX]);

        // Compute the hash of the provided password, using the same salt,

        // iteration count, and hash length

        byte[] testHash = pbkdf2(password, salt, iterations, hash.length);

        // Compare the hashes in constant time. The password is correct if

        // both hashes match.

        return slowEquals(hash, testHash);

    }

    /**
     * Compares two byte arrays in length-constant time. This comparison method
     * <p>
     * is used so that password hashes cannot be extracted from an on-line
     * <p>
     * system using a timing attack and then attacked off-line.
     *
     * @param a the first byte array
     * @param b the second byte array
     * @return true if both byte arrays are the same, false if not
     */

    private static boolean slowEquals(byte[] a, byte[] b)

    {

        int diff = a.length ^ b.length;

        for (int i = 0; i < a.length && i < b.length; i++)

            diff |= a[i] ^ b[i];

        return diff == 0;

    }

    /**
     * Computes the PBKDF2 hash of a password.
     *
     * @param password   the password to hash.
     * @param salt       the salt
     * @param iterations the iteration count (slowness factor)
     * @param bytes      the length of the hash to compute in bytes
     * @return the PBDKF2 hash of the password
     */

    private static byte[] pbkdf2(char[] password, byte[] salt, int iterations, int bytes)

            throws NoSuchAlgorithmException, InvalidKeySpecException

    {

        PBEKeySpec spec = new PBEKeySpec(password, salt, iterations, bytes * 8);

        SecretKeyFactory skf = SecretKeyFactory.getInstance(PBKDF2_ALGORITHM);

        return skf.generateSecret(spec).getEncoded();

    }

    /**
     * Converts a string of hexadecimal characters into a byte array.
     *
     * @param hex the hex string
     * @return the hex string decoded into a byte array
     */

    private static byte[] fromHex(String hex)

    {

        byte[] binary = new byte[hex.length() / 2];

        for (int i = 0; i < binary.length; i++)

        {

            binary[i] = (byte) Integer.parseInt(hex.substring(2 * i, 2 * i + 2), 16);

        }

        return binary;

    }

    /**
     * Converts a byte array into a hexadecimal string.
     *
     * @param array the byte array to convert
     * @return a length*2 character string encoding the byte array
     */

    private static String toHex(byte[] array)

    {

        BigInteger bi = new BigInteger(1, array);

        String hex = bi.toString(16);

        int paddingLength = (array.length * 2) - hex.length();

        if (paddingLength > 0)

            return String.format("%0" + paddingLength + "d", 0) + hex;

        else

            return hex;

    }

    /**
     * Tests the basic functionality of the PasswordUtils class
     *
     * @param args ignored
     */

    public static void main(String[] args)

    {
        long start = System.currentTimeMillis();
        try {
            //String str = "1024:231967094e1a2f74125d2609a2eaf8ecb4635a0925c6ef81:0be0276340294f8e2d889ec45ab6a7b08496fcbe63766bef";

            System.out.println(PasswordUtils.createHash("admin"));
           /* System.out.println("------------------------------------");
            System.out.println(PasswordUtils.createHash("123"));
            System.out.println("------------------------------------");
			
			*//*System.out.println(PasswordUtils.createHash("123").length());
			System.out.println("------------------------------------");
			
			String hashs2 = PasswordUtils.createHash("123");*//*
            System.out.println(PasswordUtils.validatePassword("admin", str));
            System.out.println("------------------------------------");*/

            long end = System.currentTimeMillis();

            System.out.println(end - start);
        } catch (Exception ex) {
            ex.printStackTrace();
            System.out.println("ERROR: " + ex);
        }
    }

}